1. Field of the Invention
Apparatuses consistent with the present invention relate to a wide angle diffuser and a liquid crystal display (LCD) employing the same, and more particularly, to a wide angle diffuser which can diffuse light that is collimated by passing the light through a liquid crystal panel to obtain a sufficient viewing angle, and a liquid crystal display (LCD) employing the same.
2. Description of the Related Art
In a conventional LCD, the light supplied to a liquid crystal panel is diffuse light. The liquid crystal panel performs a shutter function to transmit or block light by changing the polarization direction of linearly polarized input light. When diffuse light is used, a degree of change in the polarization direction varies according to the direction in which the light is incident so that a contrast ratio varies according to a viewing direction.
Even though the decrease of the contrast ratio can be restricted using a phase difference film, in an LCD achieving a viewing angle of 170°, the contrast ratio in the vertical direction is about several thousand to one, but is reduced to ten to one at an angle of 85° on the left/right side. Consequently, in an LCD supplying diffuse light to the liquid crystal panel, the display quality of a display device is considerably deteriorated at large angles. Also, to secure the viewing angle, a liquid crystal mode compensating for the deterioration in the performance of liquid crystal using a viewing angle compensation film or a variety of methods such as an IPS (in plane switching) mode, a VA (vertical alignment) mode, and an OCB (optical compensated bend) mode is provided. However, these solutions may increase costs due to the decrease in aperture ratio and increase in the number of manufacturing steps.
Thus, to solve the problem occurring when the diffuse light is incident on the liquid crystal panel, there is an increasing demand for an LCD having a structure in which collimated light is supplied to the liquid crystal panel and transmitted perpendicularly through the liquid crystal panel and having a diffuser to secure a viewing angle characteristic.